Method and apparatus for controlling interference in wireless power transmission system

ABSTRACT

An interference control method of a power transmitting unit (PTU) includes determining whether the PTU is in an interference environment in which interference by a neighbor PTU occurs, and controlling a communication parameter of either one or both of the neighbor PTU and a power receiving unit (PRU) in response to a result of the determining being that the PTU is in the interference environment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/332,758, filed on Jul. 16, 2014, which claims the benefit under 35USC 119(a) of Korean Patent Application No. 10-2013-0086340, filed onJul. 22, 2013, in the Korean Intellectual Property Office, the entiredisclosure of which is incorporated herein by reference for allpurposes.

BACKGROUND 1. Field

The following description relates to an apparatus and a method forcontrolling interference in a wireless power transmission system.

2. Description of Related Art

Wireless power is energy that is transmitted from a power transmittingunit (PTU) to a power receiving unit (PRU) through magnetic coupling.Accordingly, a wireless power transmission system or a wireless powercharging system includes a source device and a target device. The sourcedevice wirelessly transmits power, and the target device wirelesslyreceives power. The source device may be referred to as a source or aPTU, and the target device may be referred to as a target or a PRU.

The source device includes a source resonator, and the target deviceincludes a target resonator. Magnetic coupling or resonant couplingoccurs between the source resonator and the target resonator.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

In one general aspect, an interference control method of a powertransmitting unit (PTU) includes determining whether the PTU is in aninterference environment in which interference by a neighbor PTU occurs;and controlling a communication parameter of either one or both of theneighbor PTU and a power receiving unit PRU in response to a result ofthe determining being that the PTU is in the interference environment.

The communication parameter may include any one or any combination of acommunication time, a transmission power, and a communication frequency.

The controlling may include controlling a magnitude of the transmissionpower.

The transmission power may include a wake-up power.

The controlling may include controlling a frequency hopping interval ofthe communication frequency.

The PTU and the neighbor PTU may be in a network that has beenarbitrarily configured; and any one or any combination of acommunication time, a transmission power, and a communication frequencyof the neighbor PTU may be preset.

The determining may include detecting a communication error rate incommunication between the PTU and the neighbor PTU; and determiningwhether the PTU is in the interference environment based on the detectedcommunication error rate.

The determining may include detecting a number of neighbor PTUs; anddetermining whether the PTU is in the interference environment based onthe detected number of the neighbor PTUs.

The determining may include detecting a received signal strengthindicator (RSSI) of the neighbor PTU or the PRU; and determining whetherthe PTU is in the interference environment based on the detected RSSI.

The determining may include detecting a frequency channel being used bythe neighbor PTU; and determining whether the PTU is in the interferenceenvironment based on the detected frequency channel.

The method may further include configuring a network including the PTUand the neighbor PTU.

The PTU may be configured to operate in a master mode.

The method may further include configuring a network including the PTU;and the neighbor PTU may be configured to configure the networkincluding the PTU.

The may further include configuring a network including the PTU; and theneighbor PTU may be configured to configure a network that is differentfrom the network including the PTU.

The controlling may include controlling an interval of a report signalto be received from the PRU.

The report signal may include any one or any combination of informationon power received by the PRU, information on a state of the PRU, andinformation on a temperature of the PRU.

The controlling may include controlling either one or both of atransmission interval and a transmission start time of a signaltransmitted by the neighbor PTU.

The signal transmitted by the neighbor PTU may include a beacon signal.

The method may further include sharing information on the communicationparameter with the neighbor PTU.

In another general aspect, a power transmitting unit (PTU) includes aninterference environment determiner configured to determine whether thePTU is in an interference environment in which interference by aneighbor PTU occurs; and a communication parameter controller configuredto control a communication parameter of either one or both of theneighbor PTU and a power receiving unit (PRU) in response to theinterference environment determiner determining that the PTU is in theinterference environment.

In another general aspect, an interference control method of a powertransmitting unit (PTU) includes determining whether a neighbor PTU isinterfering with the PTU or has a potential to interfere with the PTU;and controlling either one or both of the neighbor PTU and a powerreceiving unit (PRU) to prevent the neighbor PTU from interfering withthe PTU in response to a result of the determining being that theneighbor PTU is interfering with the PTU or has a potential to interferewith the PTU.

The PTU may be configured to operate as a master device in a network;and the neighbor PTU may be configured to operate as a slave device inthe network.

The PTU and the neighbor PTU may be connected to a network that has beenarbitrarily configured under authorization of a host; and at least onecommunication parameter of each of the PTU and the neighbor PTU may bepreset by the host.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless power transmission system.

FIGS. 2A and 2B illustrate examples of a distribution of a magneticfield in a feeder and a resonator.

FIGS. 3A and 3B illustrate an example of a wireless power transmissionapparatus.

FIG. 4A illustrates an example of a distribution of a magnetic fieldinside a resonator produced by feeding a feeder.

FIG. 4B illustrates an example of equivalent circuits of a feeder and aresonator.

FIG. 5 illustrates an example of an interference control method of apower transmitting unit (PTU).

FIGS. 6A and 6B illustrate examples of an interference environment in awireless power transmission system.

FIGS. 7A through 7D illustrate examples of a network of PTUs.

FIGS. 8A through 8C examples of a report signal.

FIGS. 9A and 9B illustrate an example of controlling a transmissioninterval and a transmission start time.

FIG. 10 illustrates an example of controlling a frequency hoppinginterval.

FIG. 11 is a perspective view for describing an interference controlmethod of a PTU in an arbitrary network.

FIG. 12 illustrates an example of a PTU.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be apparent to one of ordinary skill inthe art. The sequences of operations described herein are merelyexamples, and are not limited to those set forth herein, but may bechanged as will be apparent to one of ordinary skill in the art, withthe exception of operations necessarily occurring in a certain order.Also, descriptions of functions and constructions that are well known toone of ordinary skill in the art may be omitted for increased clarityand conciseness.

Throughout the drawings and the detailed description, the same referencenumerals refer to the same elements. The drawings may not be to scale,and the relative size, proportions, and depiction of elements in thedrawings may be exaggerated for clarity, illustration, and convenience.

Schemes of communication between a source and a target or between asource and another source may include an in-band communication schemeand an out-of-band communication scheme.

In the in-band communication scheme, the source and the target, or thesource and the other source, communicate with each other using afrequency that is the same as a frequency used for power transmission.

In the out-of-band communication scheme, the source and the target, orthe source and the other source, communicate with each other using afrequency that is different from a frequency used for powertransmission.

FIG. 1 illustrates an example of a wireless power transmission system.

Referring to FIG. 1, the wireless power transmission system includes asource 110 and a target 120. The source 110 is a device configured tosupply wireless power, and may be any electronic device capable ofsupplying power, for example, a pad, a terminal, a tablet personalcomputer (PC), a television (TV), a medical device, or an electricvehicle. The target 120 is a device configured to receive wirelesspower, and may be any electronic device requiring power to operate, forexample, a pad, a terminal, a tablet PC, a medical device, an electricvehicle, a washing machine, a radio, or a lighting system.

The source 110 includes a variable switching mode power supply (SMPS)111, a power amplifier (PA) 112, a matching network 113, a transmission(Tx) controller 114 (for example, Tx control logic), a communicationunit 115, and a power detector 116.

The variable SMPS 111 generates a direct current (DC) voltage byswitching an alternating current (AC) voltage having a frequency in aband of tens of hertz (Hz) output from a power supply. The variable SMPS111 may output a fixed DC voltage, or may output an adjustable DCvoltage that may be adjusted under control of the Tx controller 114.

The variable SMPS 111 may control its output voltage supplied to the PA112 based on a level of power output from the PA 112 so that the PA 112may operate in a saturation region with a high efficiency at all times,thereby enabling a maximum efficiency to be maintained at all levels ofthe output power of the PA 112. The PA 112 may be, for example, aclass-E amplifier.

If a fixed SMPS is used instead of the variable SMPS 111, a variableDC-to-DC (DC/DC) converter may be necessary. In this example, the fixedSMPS outputs a fixed DC voltage to the variable DC/DC converter, and thevariable DC/DC converter controls its output voltage supplied to the PA112 based on the level of the power output from the PA 112 so that thePA 112, which may be a Class-E amplifier, may operate in the saturationregion with a high efficiency at all times, thereby enabling the maximumefficiency to be maintained at all levels of the output power.

The power detector 116 detects an output current and an output voltageof the variable SMPS 111, and transmits, to the Tx controller 114,information on the detected output current and the detected outputvoltage. Additionally, the power detector 116 may detect input currentand input voltage of the PA 112.

The PA 112 generates power by converting a DC voltage having apredetermined level supplied to the PA 112 by the variable SMPS 111 toan AC voltage using a switching pulse signal having a frequency in aband of a few megahertz (MHz) to tens of MHz. For example, the PA 112may convert the DC voltage supplied to the PA 112 to an AC voltagehaving a reference resonant frequency F_(Ref), and may generatecommunication power used for communication, and/or charging power usedfor charging. The communication power and the charging power may be usedin a plurality of targets.

If a high power from a few kilowatts (kW) to tens of kW is transmittedusing a resonant frequency in a band of tens of kilohertz (kHz) tohundreds of kHz, the PA 112 may be omitted, and power may be supplied toa source resonator 131 from the variable SMPS 111 or a high-powersupply. For example, an inverter may be used in lieu of the PA 112. Theinverter may convert a DC power supplied from the high-power powersupply to an AC power. The inverter may convert the power by convertinga DC voltage having a predetermined level to an AC voltage using aswitching pulse signal having a frequency in a band of tens of kHz tohundreds of kHz. For example, the inverter may convert the DC voltagehaving the predetermined level to an AC voltage having a resonantfrequency of the source resonator 131 in a band of tens of kHz tohundreds of kHz.

As used herein, the term “communication power” refers to a low power of0.1 milliwatt (mW) to 1 mW. The term “charging power” refers to a highpower of a few mW to tens of kW consumed by a device load of a target.As used herein, the term “charging” refers to supplying power to a unitor element configured to charge a battery or other rechargeable device.Additionally, the term “charging” refers to supplying power to a unit orelement configured to consume power. For example, the term “chargingpower” may refer to power consumed by a target while operating, or powerused to charge a battery of the target. The units or element may be, forexample, a battery, a display device, a sound output circuit, a mainprocessor, or any of various types of sensors.

As used herein, the term “reference resonant frequency” refers to aresonant frequency nominally used by the source 110. Additionally, theterm “tracking frequency” refers to a resonant frequency used by thesource 110 that has been adjusted based on a preset scheme.

The Tx controller 114 may detect a reflected wave of the communicationpower or the charging power, and may detect mismatching that may occurbetween a target resonator 133 and the source resonator 131 based on thedetected reflected wave. To detect the mismatching, for example, the Txcontroller 114 may detect an envelope of the reflected wave, a poweramount of the reflected wave, or any other characteristic of thereflected wave that is affected by mismatching.

The matching network 113 compensates for impedance mismatching betweenthe source resonator 131 and the target resonator 133 to achieve optimalmatching under the control of the Tx controller 114. The matchingnetwork 113 includes at least one inductor and at least one capacitoreach connected to a respective switch controlled by the Tx controller114.

If a high power is to be transmitted using a resonant frequency in aband of tens of kHz to hundreds of kHz, the matching network 113 may beomitted from the source 110 because the effect of the matching network113 may be reduced when transmitting a high power.

The Tx controller 114 may calculate a voltage standing wave ratio (VSWR)based on a voltage level of the reflected wave and a level of an outputvoltage of the source resonator 131 or the PA 112. In one example, ifthe VSWR is greater than a predetermined value, the Tx controller 114may determine that a mismatch is detected between the source resonator131 and the target resonator 133.

In another example, if the Tx controller 114 detects that the VSWR isgreater than the predetermined value, the Tx controller 114 maycalculate a wireless power transmission efficiency for each of Ntracking frequencies, determine a tracking frequency F_(Best) providingthe best wireless power transmission efficiency among the N trackingfrequencies, and adjust the reference resonant frequency F_(Ref) to thetracking frequency F_(Best). The N tracking frequencies may be set inadvance.

The Tx controller 114 may adjust a frequency of the switching pulsesignal used by the PA 112. The frequency of the switching pulse signalmay be determined under the control of the Tx controller 114. Forexample, by controlling the PA 112, the Tx controller 114 may generate amodulated signal to be transmitted to the target 120. In other words,the communication unit 115 may transmit a variety of data to the target120 using in-band communication. The Tx controller 114 may also detect areflected wave, and may demodulate a signal received from the target 120from an envelope of the detected reflected wave.

The Tx controller 114 may generate a modulated signal for in-bandcommunication using various methods. For example, the Tx controller 114may generate the modulated signal by turning the switching pulse signalused by the PA 112 on and off, by performing delta-sigma modulation, orby any other modulation method known to one of ordinary skill in theart. Additionally, the Tx controller 114 may generate a pulse-widthmodulated (PWM) signal having a predetermined envelope.

The Tx controller 114 may determine an initial wireless power to betransmitted to the target 120 based on a change in a temperature of thesource 110, a battery state of the target 120, a change in an amount ofpower received at the target 120, and/or a change in a temperature ofthe target 120.

The source 110 may further include a temperature measurement sensor (notillustrated) configured to detect a change in a temperature of thesource 110. The source 110 may receive from the target 120 informationregarding the battery state of the target 120, the change in the amountof power received at the target 120, and/or the change in thetemperature of the target 120 by communicating with the target 120. Thesource 110 may detect the change in the temperature of the target 120based on the information received from the target 120.

The Tx controller 114 may adjust a voltage supplied to the PA 112 basedon the change in the temperature of the target 120 using a lookup table.The lookup table may store a level of the voltage to be supplied to thePA 112 based on the change in the temperature of the source 110. Forexample, when the temperature of the source 110 rises, the Tx controller114 may reduce the voltage to be supplied to the PA 112 by controllingthe variable SMPS 111.

The communication unit 115 may perform out-of-band communication using aseparate communication channel. The communication unit 115 may include acommunication module, such as a ZigBee module, a Bluetooth module, orany other communication module known to one of ordinary skill in the artthat the communication unit 115 may use to transmit or receive data 140to or from the target 120 using the out-of-band communication.

The source resonator 131 transmits electromagnetic energy 130 to thetarget resonator 133. For example, the source resonator 131 may transmitthe communication power or charging power to the target 120 throughmagnetic coupling with the target resonator 133.

The source resonator 131 may be made of a superconducting material. Inaddition, although not shown in FIG. 1, the source resonator 131 may bedisposed in a container of refrigerant to enable the source resonator131 to maintain a superconducting state. A heated refrigerant that hastransitioned to a gaseous state may be liquefied to a liquid state by acooler. The target resonator 133 may also be made of a superconductingmaterial. In this instance, the target resonator 133 may also bedisposed in a container of refrigerant to enable the target resonator133 to maintain a superconducting state.

As illustrated in FIG. 1, the target 120 includes a matching network121, a rectifier 122, a DC/DC converter 123, a communication unit 124, areception (Rx) controller 125 (for example, Rx control logic), a voltagedetector 126, and a power detector 127.

The target resonator 133 receives the electromagnetic energy 130 fromthe source resonator 131. For example, the target resonator 133 mayreceive the communication power or the charging power from the source110 through a magnetic coupling with the source resonator 131.Additionally, the target resonator 133 may receive data from the source110 using the in-band communication.

The target resonator 133 may receive the initial wireless powerdetermined by the Tx controller 114 based on the change in thetemperature of the source 110, the battery state of the target 120, thechange in the amount of power received at the target 120, and/or thechange in the temperature of the target 120.

The matching network 121 matches an input impedance viewed from thesource 110 to an output impedance viewed from a load of the target 120.The matching network 121 may be configured to have at least onecapacitor and at least one inductor.

The rectifier 122 generates a DC voltage by rectifying AC voltagereceived from the target resonator 133.

The DC/DC converter 123 adjusts a level of the DC voltage output fromthe rectifier 122 based on a voltage required by the load. As anexample, the DC/DC converter 123 may adjust the level of the DC voltageoutput from the rectifier 122 to a level in a range from 3 volts (V) to10 V.

The voltage detector 126 detects a voltage of an input terminal of theDC/DC converter 123, and the power detector 127 detects a current and avoltage of an output terminal of the DC/DC converter 123. The detectedvoltage of the input terminal may be used to calculate a wireless powertransmission efficiency of power the received from the source 110.Additionally, the detected current and the detected voltage of theoutput terminal may be used by the Rx controller 125 to calculate anamount of power actually transferred to the load. The Tx controller 114of the source 110 may calculate an amount of power that needs to betransmitted by the source 110 to the target 120 based on an amount ofpower required by the load and the amount of power actually transferredto the load.

If the amount of the power actually transferred to the load calculatedby the RC controller 125 is transmitted to the source 110 by thecommunication unit 124, the source 110 may calculate an amount of powerthat needs to be transmitted to the target 120.

The Rx controller 125 may perform in-band communication to transmit orreceive data using a resonant frequency. During the in-bandcommunication, the Rx controller 125 may demodulate a received signal bydetecting a signal between the target resonator 133 and the rectifier122, or detecting an output signal of the rectifier 122. In other words,the Rx controller 125 may demodulate a message received using thein-band communication.

Additionally, the Rx controller 125 may adjust an impedance of thetarget resonator 133 using the matching network 121 to modulate a signalto be transmitted to the source 110. For example, the Rx controller 125may adjust the matching unit to increase the impedance of the targetresonator 133 so that a reflected wave will be detected by the Txcontroller 114 of the source 110. Depending on whether the reflectedwave is detected, the Tx controller 114 may detect a first value, forexample, a binary number “0,” or a second value, for example, a binarynumber “1.” For example, when the reflected wave is detected, the Txcontroller 114 may detect “0”, and when the reflected wave is notdetected, the Tx controller 114 may detect “1”. Alternatively, when thereflected wave is detected, the Tx controller 114 may detect “1”, andwhen the reflected wave is not detected, the Tx controller 114 maydetect “0”.

The communication unit 124 of the target 120 may transmit a responsemessage to the communication unit 115 of the source 110. For example,the response message may include any one or any combination of a producttype of the target 120, manufacturer information of the target 120, amodel name of the target 120, a battery type of the target 120, acharging scheme of the target 120, an impedance value of a load of thetarget 120, information on characteristics of the target resonator 133of the target 120, information on a frequency band used by the target120, an amount of power consumed by the target 120, an identifier (ID)of the target 120, product version information of the target 120,standard information of the target 120, and any other information aboutthe target 120.

The communication unit 124 may perform out-of-band communication using aseparate communication channel. For example, the communication unit 124may include a communication module, such as a ZigBee module, a Bluetoothmodule, or any other communication module known to one of ordinary skillin the art that the communication unit 124 may use to transmit andreceive the data 140 to and from the source 110 using the out-of-bandcommunication.

The communication unit 124 may receive a wake-up request message fromthe source 110, and the power detector 127 may detect an amount of powerreceived to the target resonator 133. The communication unit 124 maytransmit to the source 110 information on the detected amount of thepower received by the target resonator 133. The information on thedetected amount of the power received by the target resonator 133 mayinclude, for example, an input voltage value and an input current valueof the rectifier 122, an output voltage value and an output currentvalue of the rectifier 122, an output voltage value and an outputcurrent value of the DC/DC converter 123, and any other informationabout the detected amount of the power received by the target resonator133.

In the following description of FIGS. 2A through 4B, unless otherwiseindicated, the term “resonator” may refer to both a source resonator,and a target resonator. The resonator in FIGS. 2A through 4B may be usedas the resonators described with respect to FIGS. 1 and 5-12.

FIGS. 2A and 2B illustrate examples of a distribution of a magneticfield in a feeder and a resonator. When a resonator receives powersupplied through a separate feeder, a magnetic field is generated inboth the feeder and the resonator. A source resonator and a targetresonator may each have a dual loop structure including an external loopand an internal loop.

FIG. 2A is a diagram illustrating an example of a structure of awireless power transmitter in which a feeder 210 and a resonator 220 donot have a common ground. Referring to FIG. 2A, when an input currentflows into a feeder 210 through a terminal labeled “+” and out of thefeeder 210 through a terminal labeled “−”, a magnetic field 230 isgenerated by the input current. A direction 231 of the magnetic field230 inside the feeder 210 is into the plane of FIG. 2A, and is oppositeto a direction 233 of the magnetic field 230 outside the feeder 210,which is out of the plane of FIG. 2A. The magnetic field 230 generatedby the feeder 210 induces a current to flow in the resonator 220. Adirection of the induced current in the resonator 220 is opposite to adirection of the input current in the feeder 210 as indicated by thelines with arrowheads in FIG. 2A.

The induced current in the resonator 220 generates a magnetic field 240.Directions of the magnetic field 240 generated by the resonator 220 arethe same all positions inside the resonator 220, and are out of theplane of FIG. 2A. Accordingly, a direction 241 of the magnetic field 240generated by the resonator 220 inside the feeder 210 is the same as adirection 243 of the magnetic field 240 generated by the resonator 220outside the feeder 210.

Consequently, when the magnetic field 230 generated by the feeder 210and the magnetic field 240 generated by the resonator 220 are combined,a strength of the total magnetic field decreases inside the feeder 210,but increases outside the feeder 210. Accordingly, when power issupplied to the resonator 220 through the feeder 210 configured asillustrated in FIG. 2A, the strength of the total magnetic fielddecreases in the portion of the resonator 220 inside the feeder 210, butincreases in the portion of the resonator 220 outside the feeder 210.When a magnetic field is randomly distributed in the resonator 220, itmay be difficult to perform impedance matching because an inputimpedance may frequently vary. Additionally, when the strength of thetotal magnetic field increases, a wireless power transmission efficiencyincreases. Conversely, when the strength of the total magnetic fielddecreases, the wireless power transmission efficiency decreases.Accordingly, the wireless power transmission efficiency may be reducedon average.

FIG. 2B illustrates an example of a structure of a wireless powertransmission apparatus in which a resonator 250 and a feeder 260 have acommon ground. The resonator 250 includes a capacitor 251. The feeder260 receives an radio frequency (RF) signal via a port 261. When the RFsignal is input to the feeder 260, an input current is generated in thefeeder 260. The input current flowing in the feeder 260 generates amagnetic field, and a current is induced in the resonator 250 by themagnetic field. Additionally, another magnetic field is generated by theinduced current flowing in the resonator 250. In this example, adirection of the input current flowing in the feeder 260 is opposite toa direction of the induced current flowing in the resonator 250.Accordingly, in a region between the resonator 250 and the feeder 260, adirection 271 of the magnetic field generated by the input current isthe same as a direction 273 of the magnetic field generated by theinduced current, and thus the strength of the total magnetic fieldincreases. Conversely, inside the feeder 260, a direction 281 of themagnetic field generated by the input current is opposite to a direction283 of the magnetic field generated by the induced current, and thus thestrength of the total magnetic field decreases. Therefore, the strengthof the total magnetic field decreases in the portion of the resonator250 inside the feeder 260, but decreases in the portion of the resonator250 outside the feeder 260.

An input impedance may be adjusted by adjusting an internal area of thefeeder 260. The input impedance refers to an impedance viewed from thefeeder 260 to the resonator 250. When the internal area of the feeder260 increases, the input impedance increases, and when the internal areaof the feeder 260 decreases, the input impedance decreases. However, ifthe magnetic field is randomly or not uniformly distributed in theresonator 250, the input impedance may vary based on a location of atarget even if the internal area of the feeder 260 has been adjusted toadjust the input impedance to match an output impedance of a poweramplifier for a specific location of the target device. Accordingly, aseparate matching network may be needed to match the input impedance tothe output impedance of the power amplifier. For example, when the inputimpedance increases, a separate matching network may be needed to matchthe increased input impedance to a relatively low output impedance ofthe power amplifier.

FIGS. 3A and 3B illustrate an example of a wireless power transmissionapparatus.

Referring to FIG. 3A, the wireless power transmission apparatus includesa resonator 310, and a feeder 320. The resonator 310 includes acapacitor 311. The feeder 320 is electrically connected to both ends ofthe capacitor 311.

FIG. 3B illustrates in greater detail a structure of the wireless powertransmission apparatus of FIG. 3A. The resonator 310 includes a firsttransmission line (not identified by a reference numeral in FIG. 3B, butformed by various elements in FIG. 3B as discussed below), a firstconductor 341, a second conductor 342, and at least one capacitor 350.

The capacitor 350 is connected in series between a first signalconducting portion 331 and a second signal conducting portion 332 in thefirst transmission line, causing an electric field to be concentrated inthe capacitor 350. In general, a transmission line includes at least oneconductor in an upper portion of the transmission line, and at least oneconductor disposed in a lower portion of the first transmission line. Acurrent may flow through the at least one conductor disposed in theupper portion of the first transmission line, and the at least oneconductor disposed in the lower portion of the first transmission linemay be electrically grounded. In the example in FIG. 3B, a conductordisposed in the upper portion of the first transmission line isseparated into two portions that will be referred to as the first signalconducting portion 331 and the second signal conducting portion 332, anda conductor disposed in the lower portion of the first transmission linewill be referred to as a first ground conducting portion 333.

As illustrated in FIG. 3B, the resonator 310 has a generallytwo-dimensional (2D) structure. The first transmission line includes thefirst signal conducting portion 331 and the second signal conductingportion 332 in the upper portion of the first transmission line, and thefirst ground conducting portion 333 in the lower portion of the firsttransmission line. The first signal conducting portion 331 and thesecond signal conducting portion 332 are disposed to face the firstground conducting portion 333. A current flows through the first signalconducting portion 331 and the second signal conducting portion 332.

Additionally, one end of the first signal conducting portion 331 isconnected to one end of the first conductor 341, the other end of thefirst signal conducting portion 331 is connected to one end of thecapacitor 350, and the other end of the first conductor 341 is connectedto one end of the first ground conducting portion 333. One end of thesecond signal conducting portion 332 is connected to one end of thesecond conductor 342, the other end of the second signal conductingportion 332 is connected to the other end of the capacitor 350, and theother end of the second conductor 341 is connected to the other end ofthe first ground conducting portion 333. Accordingly, the first signalconducting portion 331, the second signal conducting portion 332, thefirst ground conducting portion 333, the first conductor 341, and thesecond conductor 342 are connected to one other, causing the resonator310 to have an electrically closed loop structure. The term “loopstructure” includes a polygonal structure, a circular structure, arectangular structure, and any other geometrical structure that isclosed, i.e., a geometrical structure that does not have any opening inits perimeter. The expression “having a loop structure” indicates astructure that is electrically closed.

The capacitor 350 is inserted into an intermediate portion of the firsttransmission line. In the example in FIG. 3B, the capacitor 350 isinserted into a space between the first signal conducting portion 331and the second signal conducting portion 332. The capacitor 350 may be alumped element capacitor, a distributed element capacitor, or any othertype of capacitor known to one of ordinary skill in the art. Forexample, a distributed element capacitor may include zigzagged conductorlines and a dielectric material having a high permittivity disposedbetween the zigzagged conductor lines.

The capacitor 350 inserted into the first transmission line may causethe resonator 310 to have a characteristic of a metamaterial. Ametamaterial is a material having an electrical characteristic that isnot found in nature, and thus may have an artificially designedstructure. All materials existing in nature have a magnetic permeabilityand a permittivity. Most materials have a positive magnetic permeabilityand/or a positive permittivity.

In the case of most materials, a right-hand rule may be applied to anelectric field, a magnetic field, and a Poynting vector, so thecorresponding materials may be referred to as right-handed materials(RHMs). However, a metamaterial having a magnetic permeability and/or apermittivity that is not found in nature may be classified into anepsilon negative (ENG) material, a mu negative (MNG) material, a doublenegative (DNG) material, a negative refractive index (NRI) material, aleft-handed (LH) material, and any other metamaterial classificationknown to one of ordinary skill in the art based on a sign of thepermittivity of the metamaterial and a sign of the magnetic permeabilityof the metamaterial.

If the capacitor 350 is a lumped element capacitor and a capacitance ofthe capacitor 350 is appropriately determined, the resonator 310 mayhave a characteristic of a metamaterial. If the resonator 310 is causedto have a negative magnetic permeability by appropriately adjusting thecapacitance of the capacitor 350, the resonator 310 may also be referredto as an MNG resonator. Various criteria may be applied to determine thecapacitance of the capacitor 350. For example, the various criteria mayinclude a criterion for enabling the resonator 310 to have thecharacteristic of the metamaterial, a criterion for enabling theresonator 310 to have a negative magnetic permeability at a targetfrequency, a criterion for enabling the resonator 310 to have azeroth-order resonance characteristic at the target frequency, and anyother suitable criterion. Based on any one or any combination of theaforementioned criteria, the capacitance of the capacitor 350 may beappropriately determined.

The resonator 310, hereinafter referred to as the MNG resonator 310, mayhave a zeroth-order resonance characteristic of having a resonantfrequency when a propagation constant is “0”. When the resonator 310 hasthe zeroth-order resonance characteristic, the resonant frequency isindependent of a physical size of the MNG resonator 310. The resonantfrequency of the MNG resonator 310 having the zeroth-ordercharacteristic may be changed without changing the physical size of theMNG resonator 310 by changing the capacitance of the capacitor 350.

In a near field, the electric field is concentrated in the capacitor 350inserted into the first transmission line, causing the magnetic field tobecome dominant in the near field. The MNG resonator 310 has arelatively high Q-factor when the capacitor 350 is lumped elementcapacitor, thereby increasing a wireless power transmission efficiency.The Q-factor indicates a level of an ohmic loss or a ratio of areactance with respect to a resistance in the wireless powertransmission. As will be understood by one of ordinary skill in the art,the wireless power transmission efficiency will increase as the Q-factorincreases.

Although not illustrated in FIG. 3B, a magnetic core passing through theMNG resonator 310 may be provided to increase a wireless powertransmission distance.

Referring to FIG. 3B, the feeder 320 includes a second transmission line(not identified by a reference numeral in FIG. 3B, but formed by variouselements in FIG. 3B as discussed below), a third conductor 371, a fourthconductor 372, a fifth conductor 381, and a sixth conductor 382.

The second transmission line includes a third signal conducting portion361 and a fourth signal conducting portion 362 in an upper portion ofthe second transmission line, and a second ground conducting portion 363in a lower portion of the second transmission line. The third signalconducting portion 361 and the fourth signal conducting portion 362 aredisposed to face the second ground conducting portion 363. A currentflows through the third signal conducting portion 361 and the fourthsignal conducting portion 362.

Additionally, one end of the third signal conducting portion 361 isconnected to one end of the third conductor 371, the other end of thethird signal conducting portion 361 is connected to one end of the fifthconductor 381, and the other end of the third conductor 371 is connectedto one end of the second ground conducting portion 363. One end of thefourth signal conducting portion 362 is connected to one end of thefourth conductor 372, the other end of the fourth signal conductingportion 362 is connected to one end of the sixth conductor 382, and theother end of the fourth conductor 372 is connected to the other end ofthe second ground conducting portion 363. The other end of the fifthconductor 381 is connected to the first signal conducting portion 331 ator near where the first signal conducting portion 331 is connected toone end of the capacitor 350, and the other end of the sixth conductor382 is connected to the second signal conducting portion 332 at or nearwhere the second signal conducting portion 332 is connected to the otherend of the capacitor 350. Thus, the fifth conductor 381 and the sixthconductor 382 are connected in parallel with both ends of the capacitor350. The fifth conductor 381 and the sixth conductor 382 may be used asinput ports to receive an RF signal as an input.

Accordingly, the third signal conducting portion 361, the fourth signalconducting portion 362, the second ground conducting portion 363, thethird conductor 371, the fourth conductor 372, the fifth conductor 381,the sixth conductor 382, and the resonator 310 are connected to oneother, causing the resonator 310 and the feeder 320 to have anelectrically closed loop structure. The term “loop structure” includes apolygonal structure, a circular structure, a rectangular structure, andany other geometrical structure that is closed, i.e., a geometricalstructure that does not have any opening in its perimeter. Theexpression “having a loop structure” indicates a structure that iselectrically closed.

If an RF signal is input to the fifth conductor 381 or the sixthconductor 382, an input current flows through the feeder 320 and theresonator 310, generating a magnetic field that induces a current in theresonator 310. A direction of the input current flowing through thefeeder 320 is the same as a direction of the induced current flowingthrough the resonator 310, thereby causing a strength of the totalmagnetic field in the resonator 310 to increase inside the feeder 320,but decrease outside the feeder 320.

An input impedance is determined by an area of a region between theresonator 310 and the feeder 320. Accordingly, a separate matchingnetwork used to match the input impedance to an output impedance of apower amplifier may not be required. However, even if a matching networkis used, the input impedance may be adjusted by adjusting a size of thefeeder 320, and accordingly a structure of the matching network may besimplified. The simplified structure of the matching network reduces amatching loss of the matching network.

The second transmission line, the third conductor 371, the fourthconductor 372, the fifth conductor 381, and the sixth conductor 382 ofthe feeder 320 may have the same structure as the resonator 310. Forexample, if the resonator 310 has a loop structure, the feeder 320 mayalso have a loop structure. As another example, if the resonator 310 hasa circular structure, the feeder 320 may also have a circular structure.

FIG. 4A illustrates an example of a distribution of a magnetic fieldinside a resonator produced by feeding a feeder. FIG. 4A more simplyillustrates the resonator 310 and the feeder 320 of FIGS. 3A and 3B, andthe names of the various elements in FIG. 3B will be used in thefollowing description of FIG. 4A for ease of description.

A feeding operation may be an operation of supplying power to a sourceresonator in wireless power transmission, or an operation of supplyingAC power to a rectifier in wireless power transmission. FIG. 4Aillustrates a direction of input current flowing in the feeder 320, anda direction of an induced current flowing in the source resonator 310.Additionally, FIG. 4A illustrates a direction of a magnetic fieldgenerated by the input current of the feeder 320, and a direction of amagnetic field generated by the induced current of the source resonator310.

Referring to FIG. 4A, the fifth conductor 381 or the sixth conductor 382of the feeder 320 of FIG. 3A may be used as an input port 410. In FIG.4A. the sixth conductor 382 of the feeder 320 is being used as the inputport 410. The input port 410 receives an RF signal as an input. The RFsignal may be output from a power amplifier. The power amplifier mayincrease or decrease an amplitude of the RF signal based on a powerrequirement of a target. The RF signal received by the input port 410 isrepresented in FIG. 4A as an input current flowing in the feeder 320.The input current flows in a clockwise direction in the feeder 320 alongthe second transmission line of the feeder 320. The fifth conductor 381and the sixth conductor 382 of the feeder 320 are electrically connectedto the resonator 310. More specifically, the fifth conductor 381 of thefeeder 320 is connected to the first signal conducting portion 331 ofthe resonator 310, and the sixth conductor 382 of the feeder 320 isconnected to the second signal conducting portion 332 of the resonator310. Accordingly, the input current flows in both the resonator 310 andthe feeder 320. The input current flows in a counterclockwise directionin the resonator 310 along the first transmission line of the resonator310. The input current flowing in the resonator 310 generates a magneticfield, and the magnetic field induces a current in the resonator 310.The induced current flows in a clockwise direction in the resonator 310along the first transmission line of the resonator 310. The inducedcurrent in the resonator 310 supplies energy to the capacitor 311 of theresonator 310, and also generates a magnetic field. In this example, theinput current flowing in the feeder 320 and the resonator 310 of FIG. 3Ais indicated by solid lines with arrowheads in FIG. 4A, and the inducedcurrent flowing in the resonator 310 is indicated by dashed lines witharrowheads in FIG. 4A.

A direction of a magnetic field generated by a current is determinedbased on the right-hand rule. As illustrated in FIG. 4A, inside thefeeder 320, a direction 421 of the magnetic field generated by the inputcurrent flowing in the feeder 320 is the same as a direction 423 of amagnetic field generated by the induced current flowing in the resonator310. Accordingly, a strength of the total magnetic field increasesinside the feeder 320.

In contrast, as illustrated in FIG. 4A, in a region between the feeder320 and the resonator 310, a direction 433 of a magnetic field generatedby the input current flowing in the feeder 320 is opposite to adirection 431 of a magnetic field generated by the induced currentflowing in the resonator 310. Accordingly, the strength of the totalmagnetic field decreases in the region between the feeder 320 and theresonator 310.

Typically, in a resonator having a loop structure, a strength of amagnetic field decreases in the center of the resonator, and increasesnear an outer periphery of the resonator. However, referring to FIG. 4A,since the feeder 320 is electrically connected to both ends of thecapacitor 311 of the resonator 310, the direction of the induced currentin the resonator 310 is the same as the direction of the input currentin the feeder 320. Since the direction of the induced current in theresonator 320 is the same as the direction the input current in thefeeder 320, the strength of the total magnetic field increases insidethe feeder 320, and decreases outside the feeder 320. As a result, dueto the feeder 320, the strength of the total magnetic field increases inthe center of the resonator 310 having the loop structure, and decreasesnear an outer periphery of the resonator 310, thereby compensating forthe normal characteristic of the resonator 310 having the loop structurein which the strength of the magnetic field decreases in the center ofthe resonator 310, and increases near the outer periphery of theresonator 310. Thus, the strength of the total magnetic field may beconstant inside the resonator 310.

A wireless power transmission efficiency of transmitting power from asource resonator to a target resonator is proportional to the strengthof the total magnetic field generated in the source resonator. In otherwords, when the strength of the total magnetic field increases in thecenter of the source resonator, the wireless power transmissionefficiency also increases.

FIG. 4B illustrates an example of equivalent circuits of a feeder and aresonator. Referring to FIG. 4B, a feeder 440 and a resonator 450 may beexpressed by the equivalent circuits in FIG. 4B. The feeder 440 isrepresented as an inductor having an inductance L_(f), and the resonator450 is represented as a series connection of an inductor having aninductance L coupled to the inductance L_(f) of the feeder 440 by amutual inductance M, a capacitor having a capacitance C, and a resistorhaving a resistance R. An example of an input impedance Z_(in) viewed ina direction from the feeder 440 to the resonator 450 may be expressed bythe following Equation 1.

$\begin{matrix}{Z_{in} = \frac{\left( {\omega \; M} \right)^{2}}{Z}} & (1)\end{matrix}$

In Equation 1, M denotes a mutual inductance between the feeder 440 andthe resonator 450, ω denotes a resonant frequency between the feeder 440and the resonator 450, and Z denotes an impedance viewed in a directionfrom the resonator 450 to a target. As can be seen from Equation 1, theinput impedance Z_(in) is proportional to the square of the mutualinductance M. Accordingly, the input impedance Z_(in) may be adjusted byadjusting the mutual inductance M between the feeder 440 and theresonator 450. The mutual inductance M depends on an area of a regionbetween the feeder 440 and the resonator 450. The area of the regionbetween the feeder 440 and the resonator 450 may be adjusted byadjusting a size of the feeder 440, thereby adjusting the mutualinductance M and the input impedance Z_(in). Since the input impedanceZ_(in) may be adjusted by adjusting the size of the feeder 440, it maybe unnecessary to use a separate matching network to perform impedancematching with an output impedance of a power amplifier.

In the resonator 450 and the feeder 440 included in a wireless powerreception apparatus, a magnetic field may be distributed as illustratedin FIG. 4A. The resonator 450 may operate as a target resonator. Forexample, the target resonator may receive wireless power from a sourceresonator via magnetic coupling. The received wireless power induces acurrent in the target resonator. The induced current in the targetresonator generates a magnetic field, which induces a current in thefeeder 440. If the resonator 450 is connected to the feeder 440 asillustrated in FIG. 4A, a direction of the induced current flowing inthe resonator 450 will be the same as a direction of the induced currentflowing in the feeder 440. Accordingly, for the reasons discussed abovein connection with FIG. 4A, the strength of the total magnetic fieldwill increase inside the feeder 440, and will decrease in the regionbetween the feeder 440 and the resonator 450.

Hereinafter, for ease of description, a “source” or a “wireless powertransmission apparatus” will be referred to as a power transmitting unit(PTU). A “target” or a “wireless power reception apparatus” will bereferred to as a power receiving unit (PRU). A PTU operating in a mastermode may be referred to as a “master device”, and a PTU operating in aslave mode may be referred to as a “slave device”.

A master device may be network-connected to at least one slave device.The expression “being network-connected” refers to configuring a networkto transmit and receive data between devices. In a network, a masterdevice is a device that controls a slave device. A slave device iscontrolled by the master device.

FIG. 5 illustrates an example of an interference control method of aPTU.

Referring to FIG. 5, in 510, the PTU configures a network with aneighbor PTU. A neighbor PTU is a PTU existing in a vicinity of the PTU.There may be plurality of neighbor PTUs. Examples of operation modes ofthe PTU include a master mode and a slave mode.

The PTU may perform in-band communication or out-of-band communicationwith the neighbor PTU or a PRU. Examples of the in-band communicationinclude near field communication (NFC) and radio frequencyidentification (RFID) communication. Examples of the out-of-bandcommunication include Bluetooth communication and Bluetooth low energy(BLE) communication.

The PTU may automatically configure a network with the neighbor PTU. Inthis example, the PTU may be operated in the master mode or the slavemode. When power is supplied to the PTU, the PTU may verify whether amaster device is present in the vicinity of the PTU. In this instance,the PTU may transmit or receive a search signal using the out-of-bandcommunication to verify whether a master device is present in thevicinity of the PTU. The search signal may include an advertisementsignal. In one example, the PTU may set its operation mode to be themaster mode, and transmit or broadcast the search signal to the neighborPTU. When a response signal is received from the neighbor PTU inresponse to the search signal, the PTU may determine that a masterdevice is present in the vicinity of the PTU. When a response signal isnot received from the neighbor PTU in response to the search signal, thePTU may determine that a master device is absent in the vicinity of thePTU. In another example, the PTU may set its operation mode to be theslave mode, and receive the search signal from the neighbor PTU. Whenthe search signal is received, the PTU may determine that a masterdevice is present in the vicinity of the PTU. When a search signal isnot received, the PTU may determine that a master device is absent inthe vicinity of the PTU.

When the PTU determines that a master device is present in the vicinityof the PTU, the PTU may set its operation mode to be the slave mode.When the PTU determines that a master device is absent in the vicinityof the PTU, the PTU may set its operation mode to be the master mode.

When the PTU is operated in the master mode, the PTU may periodicallymonitor whether a slave device is present in the vicinity of the PTU.When the PTU detects a slave device in the vicinity of the PTU, the PTUmay transmit a connection request signal to the slave device. When thePTU receives a response signal from the slave device in response to theconnection request signal, the PTU may be network-connected to the slavedevice. Accordingly, the PTU may operate as a master device thatcontrols the slave device.

When the PTU operates in the slave mode, the PTU may receive aconnection request signal from the master device. The PTU may transmit aresponse signal to the master device in response to the connectionrequest signal. Accordingly, the PTU may be network-connected to themaster device.

The PTU may configure a piconet or a scatternet. A piconet is a networkin which a PTU and a neighbor PTU configure the same network, and ascatternet is a network in which a plurality of piconets are mutuallyconnected and a PTU and a neighbor PTU configure different networks.

In addition, the PTU may configure a network arbitrarily with a host.Examples of the host include devices capable of configuring a network,for example, a laptop computer, a PC, a server, and any other devicecapable of configuring a network. When the PTU configures a networkarbitrarily with the host, a number of PTUs and a number of neighborPTUs may be predetermined. The PTU may perform wired communication orwireless communication with the host. The PTU may transmit a searchsignal to a device capable of performing wired communication or wirelesscommunication with the PTU, and recognize a device responding to thesearch signal as a host. The PTU may set its operation mode to be theslave mode, and be network-connected to a found host. In this example,the host may operate as a master device, and the PTU may operate as aslave device and be network-connected to the host.

In 520, the PTU determines whether the PTU is in an interferenceenvironment in which interference by the neighbor PTU occurs. Whenneighbor PTUs are concentrated in an area having a predetermined size,interference may occur when the PTU communicates with a neighbor PTU ora PRU. When interference occurs, a signal transmitted or received by thePTU may be distorted, or a signal transmitted by the PTU may collidewith a signal transmitted by a neighbor PTU, and a transmission andreception time may be delayed. Accordingly, the PTU may determinewhether the PTU is in the interference environment, and prevent, reduce,or eliminate the interference. In this example, the PTU may operate inthe master mode, and share information, for example, a communicationparameter, with the neighbor PTU.

The PTU may determine whether the PTU is in the interference environmentbased on a communication error rate. The PTU may detect thecommunication error rate in communication performed with the neighborPTU. In one example, the PTU may detect the communication error rateusing an error detection code. The PTU may compare the detectedcommunication error rate to a predetermined reference rate. When thedetected communication error rate is lower than the predeterminedreference rate, the PTU may determine that the PTU is in an environmentin which interference does not occur. Conversely, when the detectedcommunication error rate is greater than or equal to the predeterminedreference rate, the PTU may determine that the PTU is in theinterference environment.

The PTU may determine whether the PTU is in the interference environmentbased on a number of neighbor PTUs. The PTU may detect the number of theneighbor PTUs. In this instance, the PTU may detect a neighbor PTUconfiguring the same network with the PTU, and also detect a neighborPTU configuring a network different from a network configured by thePTU. An area in which the PTU detects the number of the neighbor PTUsmay be preset. The PTU may compare the detected number of the neighborPTUs to a predetermined reference number. When the detected number ofthe neighbor PTUs is less than the predetermined reference number, thePTU may determine that the PTU is in an environment in whichinterference does not occur. When the detected number of the neighborPTUs is greater than or equal to the predetermined reference number, thePTU may determine that the PTU is in the interference environment.

The PTU may determine whether the PTU is in the interference environmentbased on a received signal strength indicator (RSSI). The PTU may detectan RSSI of the neighbor PTU or the PRU. For example, the neighbor PTU orthe PRU may measure an RSSI with respect to the PTU, and transmit themeasured RSSI to the PTU. In addition, the PTU may share the RSSImeasured by the neighbor PTU. The PTU may compare the received RSSI to apredetermined reference value. An RSSI greater than the predeterminedreference value indicates that PTUs are concentrated in an area having apredetermined size. Accordingly, when the detected RSSI is greater thanor equal to the predetermined reference value, the PTU may determinethat the PTU is in the interference environment. Conversely, when thedetected RSSI is less than the predetermined reference value, the PTUmay determine that the PTU is in an environment in which interferencedoes not occur.

The PTU may determine whether the PTU is in the interference environmentbased on a frequency channel being used. The PTU may perform out-of-bandcommunication with the neighbor PTU or the PRU. Examples of theout-of-band communication include Bluetooth communication and BLEcommunication. The Bluetooth communication may be performed using acommunication frequency in a 2.4 gigahertz (GHz) band and 79 channels,and the BLE communication may be performed using a communication in a2.4 GHz band and 40 channels. The PTU may detect a frequency channelbeing used by the neighbor PTU. The PTU may compare a number of detectedfrequency channels being used by neighbor PTUs to a predeterminedreference value. A number of frequency channels being used by neighborPTUs that is greater than or equal to the predetermined reference valuemay indicate that a number of the neighbor PTUs may be great enough tocause interference. Accordingly, when the number of the detectedfrequency channels being used by the neighbor PTUs is greater than orequal to the predetermined reference value, the PTU may determine thatthe PTU is in the interference environment. Conversely, when the numberof the frequency channels being used by the neighbor PTUs is less thanthe predetermined reference value, the PTU may determine that the PTU isin an environment in which interference does not occur.

When the PTU is in the interference environment, the PTU controls acommunication parameter of either one or both of the neighbor PTU andthe PRU in 530. The communication parameter may include any one or anycombination of a communication time, a transmission power, and acommunication frequency.

The PTU may control an interval of a report signal received from thePRU. The report signal may include a dynamic parameter representing oneor more measured values that may change while the PRU is being charged.The PTU may receive the report signal from the PRU to detect a chargingstatus of the PRU, whether the PRU is in a wireless power transmissionarea, and other information. For example, the PTU may receive the reportsignal from the PRU at 250-millisecond (ms) intervals. When atransmission error occurs in the report signal, a charging power controlerror, a PRU recognition error, and other errors may occur. In oneexample, the report signal may include any one or any combination ofinformation on power received by the PRU, information on a state of thePRU, and information on a temperature of the PRU. For example, thereport signal may include any one or any combination of an outputvoltage V_(RECT) of a rectifier, an output current I_(RECT) of therectifier, a voltage V_(OUT) of a charging or battery port, a currentI_(OUT) of the charging or battery port, a temperature of the PRU, aminimum threshold value V_(RECT) _(_) _(MIN) _(_) _(DYN) of an outputvoltage of the rectifier, a target value V_(RECT) _(_) _(SET) _(_)_(DYN) of an output voltage of the rectifier, a maximum threshold valueV_(RECT) _(_) _(HIGH) _(_) _(DYN) of an output voltage of the rectifier,and a PRU alert.

The PTU may control interference by controlling an interval of thereport signal. The neighbor PTU or the PTU receiving the report signalmay transmit a response signal responding to the report signal. Aninterval of the response signal may be the same as the interval of thereport signal.

In one example, when the intervals of the report signal and the responsesignal are relatively short in the interference environment, a number ofsignals transmitted and received in a predetermined period of time mayincrease, and thus a probability that interference may occur betweenPTUs and a PRU may increase. In this example, the PTU may control theinterval of the report signal to be relatively long, thereby decreasingthe number of the signals transmitted and received in the predeterminedperiod of time, and thus the probability that interference may occur maydecrease.

In another example, the PTU may transmit, to the PRU, a control signalsetting the interval of the report signal based on a number of neighborPTUs to which the PRU transmits report signals. The PRU receiving thecontrol signal may transmit report signals to the PRU and the neighborPTU using the report signal interval set by the PTU.

The PTU may control either one or both of a transmission interval and atransmission start time of a signal transmitted by the neighbor PTU. Thesignal may be a beacon signal. The beacon signal may be a short beaconsignal or a long beacon signal. The short beacon signal is a beaconsignal to be used for detecting whether an object, for example, a PRU ora foreign object, is present within a predetermined range. The longbeacon signal is a beacon signal to be used for waking up a PRU. Inaddition, a signal transmitted to the PRU may be another signal insteadof the beacon signal, for example, a connection request signal, acontrol signal, or a data signal.

When a plurality of PTUs transmit signals, for example, beacon signals,simultaneously to a single PRU, a cross connection may occur. A crossconnection is a communication connection error occurring due to anenvironment in which PTUs are concentrated. Accordingly, the PTU maycontrol either one or both of the transmission interval and thetransmission start time of the signal transmitted by the neighbor PTU.In one example, the PTU may control a single PTU to transmit a signal toa single PRU during a single time slot. A time slot is an identifiablepredetermined period of time. For example, the single time slot have aperiod of 625 microseconds (μs).

Since the PTU may share a communication parameter with the neighborPTUs, the PTU may obtain information on signals transmitted by theneighbor PTUs. When signals transmitted by the PTU overlap the signalstransmitted by the neighbor PTUs in a time slot, the PTU may resetinformation on the signals transmitted by the neighbor PTUs to preventthe signals transmitted by the PTU from overlapping the signalstransmitted by the neighbor PTUs.

In one example, the PTU may control a transmission start time of asignal sequence transmitted by the neighbor PTU. In a case in which atransmission interval of a signal sequence transmitted by the PTU to thePRU is the same as a transmission interval of a signal sequencetransmitted by the neighbor PTU to the PRU, when a transmission starttime of the PTU is the same as a transmission start time of the neighborPTU, the signal sequence of the PTU may coincide with the signalsequence of the neighbor PTU, and thus the PTU and the neighbor PTU maytransmit signals during the same time slot. Accordingly, the PTU may settransmission start times of the PTU and the neighbor PTU to be differentso that the PTU and the neighbor PTU may transmit signals to the PRUduring different time slots.

In another example, the PTU may control a transmission interval of asignal sequence transmitted by the neighbor PTU. A transmission intervalof a signal sequence of the PTU may be the same as or different from thetransmission interval of the signal sequence of the neighbor PTU. Whenthe transmission intervals of the signal sequences of the PTU and theneighbor PTU are the same, the PTU may set the transmission start timesof the PTU and the neighbor PTU to be different to control the signalsequences so the signal sequences do not overlap. Conversely, when thetransmission intervals of the signal sequences of the PTU and theneighbor PTU are different from each other, the signal sequences mayoverlap even though the transmission start time of the PTU is differentfrom the transmission start time of the neighbor PTU. The PTU may setthe transmission start times of the PTU and the neighbor PTU, and adjustthe transmission intervals of the signal sequences, so that the signalsequences do not overlap.

The PTU may control a magnitude of the transmission power. Thetransmission power may be a wake-up power. The PRU may perform controland communication using the wake-up power.

In one example, a great number of neighbor PTUs may be present in anarea having a predetermined size. In this example, when a relativelygreat amount of power is transmitted by a neighbor PTU to a PRU,interference may occur. Accordingly, the PTU may control the magnitudeof the transmission power of the neighbor PTU to prevent interferencecaused by the transmission power.

The PTU may control a frequency hopping interval. Frequency hoppingrefers to a technique of spreading a frequency spectrum by rapidlyswitching a transmission signal from one frequency to another frequency.The PTU may transmit a transmission signal to be distributed amongmultiple frequencies. In one example, when the PTU performs Bluetoothcommunication, the PTU may use 79 frequency hopping channels. In anotherexample, when the PTU performs BLE communication, the PTU may use 40frequency hopping channels. As used herein, the term “frequency hoppinginterval” is an interval during which all of the frequency hoppingchannels in a frequency hopping sequence are used.

In one example, the PTU and the neighbor PTU may use the same frequencyhopping sequence. For example, PTUs may configure piconets. Each piconetmay be distinguished from another piconet by using different frequencyhopping sequences. A PTU and a neighbor PTU belonging to the samepiconet may be synchronized to a same frequency hopping sequence.

As a frequency hopping interval decreases, a number of frequencychannels used by the PTU or the neighbor PTU during a predeterminedperiod of time may increase. For example, when a frequency hoppingsequence is “Channel 1—Channel 2—Channel 3” and a frequency hoppinginterval is 3 μs, the PTU and the neighbor PTU may use a singlefrequency channel for 1 μs. Conversely, when the frequency hoppinginterval decreases to 1 μs, the PTU and the neighbor PTU, may use threefrequency channels for 1 μs. Accordingly, a probability of frequencychannels used by the PTU and the neighbor PTU overlapping may increase,and a probability of interference occurring may increase. The PTU maycontrol the frequency hopping interval of the neighbor PTU to adjust thefrequency channels used by the PTU and the neighbor PTU so the frequencychannels do not overlap each other, thereby decreasing the probabilityof the interference occurring.

FIGS. 6A and 6B illustrate examples of an interference environment in awireless power transmission system.

Referring to FIG. 6A, the wireless power transmission system includesPTUs including a first PTU 610 through an N-th PTU 620, and a PRU 630.Although a single PRU 630 is shown in FIG. 6A as one example, aplurality of PRUs may be provided.

The PTUs including the first PTU 610 through the N-th PTU 620 maytransmit wireless power using magnetic coupling between a sourceresonator and a target resonator. The PTUs including the first PTU 610through the N-th PTU 620 may mutually configure networks, for example,piconets or scatternets.

In a case in which the PTUs including the first PTU 610 through the N-thPTU 620 are concentrated in an area, interference may occur when thePTUs including the first PTU 610 through the N-th PTU 620 transmitsignals to the PRU 630. Accordingly, one of the PTUs including the firstPTU 610 through the N-th PTU 620 may operate as a master device and maycontrol the interference by controlling communication parameters of theother PTUs, which may operate as slave devices.

Referring to FIG. 6B, white dots in cells of a communication area 640denote PTUs, and black dots in the cells of the communication area 640denote PRUs. In each cell, a PTU may transmit power to a PRU, andtransmit and receive data to and from the PRU. Since a single PTU isprovided in each of cells 651 and 655, a probability of interferenceoccurring between a PTU and a PRU in the cells 651 and 655 is relativelylow. However, since a plurality of PTUs are provided in each of cells652 through 654, a probability of interference occurring is relativelyhigh compared to the cells 651 and 655. To eliminate interference,communication parameters of PTUs and PRUs in the cells 652 through 654may be controlled by at least one PTU included in each of the cells 652through 654.

FIGS. 7A through 7D illustrate examples of a network of PTUs.

Referring to FIG. 7A, a network 701 of PTUs includes a master device711, a first slave device 712, and a second slave device 713. PRUs 714through 716 may be present in the network 701 among the PTUs. The PRUs714 through 716 are located in an area in which power or signals may bereceived from the master device 711, the first slave device 712, and thesecond slave device 713. The master device 711, the first slave device712, and the second slave device 713 transmit signals to the PRUs 714through 716. As an example, to wake up the PRUs 714 through 716, themaster device 711, the first slave device 712, and the second slavedevice 713 may transmit beacon signals to the PRUs 714 through 716. Inthis example, when the beacon signals are transmitted simultaneously bythe master device 711, the first slave device 712, and the second slavedevice 713, a cross connection may occur. As another example, the masterdevice 711, the first slave device 712, and the second slave device 713may transmit data signals to the PRUs 714 through 716. In this example,when frequency channels used by the master device 711, the first slavedevice 712, and the second slave device 713 overlap, an interferencesignal may be generated. Accordingly, the master device 711 may controla communication parameter of any one or any combination of the slavedevices 712 and 713 and the PRUs 714 through 716, thereby preventing anoccurrence of the cross connection and eliminating the interferencesignal.

Referring to FIG. 7B, a network 721 of PTUs includes a master device731, a first slave device 732, and a second slave device 733. PRUs 734through 736 may be located on or adjacent to the master device 731, thefirst slave device 732, and the second slave device 733, respectively.In this example, the PRUs 734 through 736 receive power or signalstransmitted by the PTUs 731 through 733, respectively. In addition, thePRUs 734 through 736 may receive power or signals transmitted byneighbor PTUs, other than the PTUs corresponding to the master device731, the first slave device 732, and the second slave device 733.Accordingly, similar to FIG. 7A, a cross connection may occur or aninterference signal may be generated. To prevent an occurrence of thecross connection or a generation of the interference signal, the masterdevice 731 may control a communication parameter of any one or anycombination of the slave devices 732 and 733 and the PRUs 734 through736, thereby preventing the occurrence of the cross connection andeliminating the interference signal.

Referring to FIG. 7C, a piconet 751 includes a master device 761 andslave devices, a piconet 752 includes a master device 762 and slavedevices, and a piconet 753 includes a master device 763 and slavedevices. The piconets 751 through 753 may be connected to each other toconfigure a scatternet. A slave device 764 is located in an area inwhich the piconet 751 and the piconet 752 overlap, and a slave device765 is located in an area in which the piconet 752 and the piconet 753overlap. The slave device 764 may perform relaying between the piconet751 and the piconet 752, and the slave device 765 may perform relayingbetween the piconet 752 and the piconet 753.

Referring to FIG. 7D, a piconet 771 includes a master device 781 andslave devices, a piconet 772 includes a master device 782 and slavedevices, and a piconet 773 includes a master device 783 and slavedevices. Similar to FIG. 7C, the piconets 771 through 773 may beconnected to each other to configure a scatternet. A master device 781is located in an area in which the piconet 771 and the piconet 772overlap, and a master device 782 is located in an area in which thepiconet 772 and the piconet 773 overlap. The master device 781 mayperform relaying between the piconet 771 and the piconet 772, and themaster device 782 may perform relaying between the piconet 772 and thepiconet 773.

In FIGS. 7C and 7D, the master devices and the slave devices may shareinformation on communication parameters. When a master device is in aninterference environment in which interference may occur, the masterdevice may control a communication parameter of a slave device. Inaddition, in a scatternet, one of the plurality of master devices maycontrol communication parameters of the other master devices and theslave devices.

FIGS. 8A through 8C illustrate examples of a report signal.

Referring to FIG. 8A, a PTU 811 unicasts or broadcasts a beacon signal821 to a PRU 812 to detect the PRU 812. The PRU 812 transmits anadvertisement signal 822 to the PTU 811, and the PTU 811 transmits aconnection request signal 823 to the PRU 812. When the PTU 811 receivesa response signal 824 responding to the connection request signal 823 isreceived, the PTU 811 is connected to the PRU 812.

The PTU 811 receives a first report signal 826 through an N-th reportsignal 827 from the PRU 812 to detect a state of the PRU 812. A reportsignal may include a dynamic parameter. As an interval of the reportsignal decreases, a transmission interval of a response signaltransmitted by the PTU 811 to the PRU 812 also decreases so thatinterference may occur. Accordingly, the PTU 811 transmits a controlsignal 825 to the PRU 812 to control the interval of the report signal.Transmission intervals of the report signals 826 through 827 may beadjusted based on the control signal 825 to eliminate the interference.

Referring to FIGS. 8B and 8C, f(k), f(k+1), and so on indicate timeslots. A time slot is an identifiable predetermined period of time. kdenotes a number of a time slot. In FIG. 8B, a PRU transmits a reportsignal at two-time slot intervals. A PTU transmits a response signalwith respect to the report signal at two-time slot intervals. In aninterference environment in which interference may occur, as theinterval of the report signal decreases, the interval of the responsesignal of the PTU also decreases, and thus a probability thatinterference may occur may increase. Accordingly, the PTU may controlthe interval of the report signal as shown in FIG. 8C.

In FIG. 8C, the PRU transmits the report signal at 3-time slot intervalsunder the control of the PTU. The PTU transmits the response signalresponding to the report signal at 3-time slot intervals. Accordingly,the probability that interference may occur may be reduced compared to acase in which the report signal is transmitted at 2-time slot intervalsas shown in FIG. 8B.

FIGS. 9A and 9B illustrate an example of controlling a transmissioninterval and a transmission start time.

Referring to FIG. 9A, transmission intervals of a PTU PTU 1 and neighborPTUs PTU 2 and PTU 3 are the same, in particular, a 3-time slotinterval. When transmission start times of the PTU and the neighbor PTUsare the same, a PRU may receive signals from the three PTUssimultaneously at 3-time slot intervals. In this example, interferencemay occur due to the neighbor PTUs. Accordingly, the PTU may control thetransmission start times of the PTU and the neighbor PTUs as shown inFIG. 9A to prevent two or more PTUs from transmitting signalssimultaneously.

Referring to FIG. 9B, a PTU PTU 1 may set transmission intervals ofneighbor PTUs, for example, a first neighbor PTU PTU 2 and a secondneighbor PTU PTU 3, differently, and transmit a signal to a PRU. The PTUmay set a transmission start time of the PTU to f(k), a transmissionstart time of the first neighbor PTU to f(k+1), and a transmission starttime of the second neighbor PTU to f(k+3). The PTU may adjusttransmission intervals of the PTU and the neighbor PTUs to prevent thePTU and the neighbor PTUs from transmitting signals simultaneously. Forexample, the PTU may set a transmission interval of the PTU to be a2-time slot interval, a transmission interval of the first neighbor PTUto be a 4-time slot interval, and a transmission interval of the secondneighbor PTU to be an 8-time slot interval.

FIG. 10 illustrates an example of controlling a frequency hoppinginterval.

Referring to FIG. 10, a PTU and a neighbor PTU may transmit signals to aPRU using out-of-band communication. In one example, the out-of-bandcommunication may be BLE communication. In a case of the BLEcommunication, a communication frequency of 2.4 GHz and 40 communicationchannels may be used. In this example, channels 0 through 36 may be usedfor transmitting and receiving data signals, and channels 37 through 39may be used for transmitting and receiving advertisement signals.

In one example, the PTU may set a frequency hopping sequence of the PTUand the neighbor PTU, and transmit signals to the PRU by controlling acommunication frequency based on the set frequency hopping sequence. Forexample, the PTU may set the frequency hopping sequence to be “Channel 11010—Channel 10 1020—Channel 14 1030—Channel 16 1040—Channel 24 1050”.

In an environment in which interference may occur, the PTU may control afrequency hopping interval of the neighbor PTU. For example, if thefrequency hopping interval is 1 μs, the neighbor PTU will use fivefrequency channels for 1 μs. When the PTU controls the frequency hoppinginterval to be 5 μs, the neighbor PTU will use a single frequencychannel for 1 μs. Accordingly, a probability of overlap occurring amongfrequency channels used by the PTU and the neighbor PTU may be reduced,and thus a probability of interference occurring may also be reduced.

FIG. 11 is a perspective view for describing an interference controlmethod of a PTU in an arbitrary network.

Referring to FIG. 11, an arbitrary network includes a host 1110, a PTU1120, and neighbor PTUs 1130 and 1140. In this example, the PTU 1120 mayoperate in a master mode, and the neighbor PTUs 1130 and 1140 mayoperate in a slave mode.

In one example, an additional PTU may be connected to the arbitrarynetwork under authorization of the host 1110. Since a number of PTUs maybe predetermined, the host 1110 may pre-calculate a range of acommunication parameter in which interference may not occur between thePTU 1120 and the neighbor PTUs 1130 and 1140. Accordingly, any one orany combination of communication times, transmission powers, andcommunication frequencies of the PTU 1120 and the neighbor PTUs 1130 and1140 may be preset by the host.

FIG. 12 illustrates an example of a PTU.

Referring to FIG. 12, a PTU 1200 includes a resonator 1210, a matchingcircuit 1220, a PA 1230, a power supply unit 1240, and a control andcommunication unit 1250.

The resonator 1210 generates magnetic field coupling with a resonator ofanother PTU or a PRU.

The matching circuit 1220 compensates for impedance mismatching betweenthe PTU 1200 and the other PTU or the PRU to achieve optimal matchingunder the control of the control and communication unit 1250.

The PA 1230 generates power by converting a DC voltage having apredetermined level to an AC voltage under the control of the controland communication unit 1250.

The power supply unit 1240 supplies power to the PA 1230 under thecontrol of the control and communication unit 1250.

The control and communication unit 1250 includes an interferenceenvironment determiner 1260 and a communication parameter controller1270. The interference environment determiner 1260 determines whetherthe PTU 1200 is in an interference environment in which interference mayoccur by a neighbor PTU. The communication parameter controller 1270controls a communication parameter of either one or both of the neighborPTU and the PRU when the interference environment determiner determinesthat the PTU 1200 is in the interference environment.

The descriptions provided with reference to FIGS. 1 through 11 may beapplied to the PTU 1200 of FIG. 12, and thus a duplicated descriptionwill be omitted for conciseness.

The Tx controller 114, the communication units 115 and 124, and the Rxcontroller 125 in FIG. 1, and the control and communication unit 1250,the interference environment determiner 1260, and the communicationparameter controller 1270 in FIG. 12 described above may be implementedusing one or more hardware components, one or more software components,or a combination of one or more hardware components and one or moresoftware components.

A hardware component may be, for example, a physical device thatphysically performs one or more operations, but is not limited thereto.Examples of hardware components include resistors, capacitors,inductors, power supplies, frequency generators, operational amplifiers,power amplifiers, low-pass filters, high-pass filters, band-passfilters, analog-to-digital converters, digital-to-analog converters, andprocessing devices.

A software component may be implemented, for example, by a processingdevice controlled by software or instructions to perform one or moreoperations, but is not limited thereto. A computer, controller, or othercontrol device may cause the processing device to run the software orexecute the instructions. One software component may be implemented byone processing device, or two or more software components may beimplemented by one processing device, or one software component may beimplemented by two or more processing devices, or two or more softwarecomponents may be implemented by two or more processing devices.

A processing device may be implemented using one or more general-purposeor special-purpose computers, such as, for example, a processor, acontroller and an arithmetic logic unit, a digital signal processor, amicrocomputer, a field-programmable array, a programmable logic unit, amicroprocessor, or any other device capable of running software orexecuting instructions. The processing device may run an operatingsystem (OS), and may run one or more software applications that operateunder the OS. The processing device may access, store, manipulate,process, and create data when running the software or executing theinstructions. For simplicity, the singular term “processing device” maybe used in the description, but one of ordinary skill in the art willappreciate that a processing device may include multiple processingelements and multiple types of processing elements. For example, aprocessing device may include one or more processors, or one or moreprocessors and one or more controllers. In addition, differentprocessing configurations are possible, such as parallel processors ormulti-core processors.

A processing device configured to implement a software component toperform an operation A may include a processor programmed to runsoftware or execute instructions to control the processor to performoperation A. In addition, a processing device configured to implement asoftware component to perform an operation A, an operation B, and anoperation C may have various configurations, such as, for example, aprocessor configured to implement a software component to performoperations A, B, and C; a first processor configured to implement asoftware component to perform operation A, and a second processorconfigured to implement a software component to perform operations B andC; a first processor configured to implement a software component toperform operations A and B, and a second processor configured toimplement a software component to perform operation C; a first processorconfigured to implement a software component to perform operation A, asecond processor configured to implement a software component to performoperation B, and a third processor configured to implement a softwarecomponent to perform operation C; a first processor configured toimplement a software component to perform operations A, B, and C, and asecond processor configured to implement a software component to performoperations A, B, and C, or any other configuration of one or moreprocessors each implementing one or more of operations A, B, and C.Although these examples refer to three operations A, B, C, the number ofoperations that may implemented is not limited to three, but may be anynumber of operations required to achieve a desired result or perform adesired task.

Software or instructions for controlling a processing device toimplement a software component may include a computer program, a pieceof code, an instruction, or some combination thereof, for independentlyor collectively instructing or configuring the processing device toperform one or more desired operations. The software or instructions mayinclude machine code that may be directly executed by the processingdevice, such as machine code produced by a compiler, and/or higher-levelcode that may be executed by the processing device using an interpreter.The software or instructions and any associated data, data files, anddata structures may be embodied permanently or temporarily in any typeof machine, component, physical or virtual equipment, computer storagemedium or device, or a propagated signal wave capable of providinginstructions or data to or being interpreted by the processing device.The software or instructions and any associated data, data files, anddata structures also may be distributed over network-coupled computersystems so that the software or instructions and any associated data,data files, and data structures are stored and executed in a distributedfashion.

For example, the software or instructions and any associated data, datafiles, and data structures may be recorded, stored, or fixed in one ormore non-transitory computer-readable storage media. A non-transitorycomputer-readable storage medium may be any data storage device that iscapable of storing the software or instructions and any associated data,data files, and data structures so that they can be read by a computersystem or processing device. Examples of a non-transitorycomputer-readable storage medium include read-only memory (ROM),random-access memory (RAM), flash memory, CD-ROMs, CD-Rs, CD+Rs, CD-RWs,CD+RWs, DVD-ROMs, DVD-Rs, DVD+Rs, DVD-RWs, DVD+RWs, DVD-RAMs, BD-ROMs,BD-Rs, BD-R LTHs, BD-REs, magnetic tapes, floppy disks, magneto-opticaldata storage devices, optical data storage devices, hard disks,solid-state disks, or any other non-transitory computer-readable storagemedium known to one of ordinary skill in the art.

Functional programs, codes, and code segments for implementing theexamples disclosed herein can be easily constructed by a programmerskilled in the art to which the examples pertain based on the drawingsand their corresponding descriptions as provided herein.

While this disclosure includes specific examples, it will be apparent toone of ordinary skill in the art that various changes in form anddetails may be made in these examples without departing from the spiritand scope of the claims and their equivalents. Suitable results may beachieved if the described techniques are performed in a different order,and/or if components in a described system, architecture, device, orcircuit are combined in a different manner, and/or replaced orsupplemented by other components or their equivalents. Therefore, thescope of the disclosure is defined not by the detailed description, butby the claims and their equivalents, and all variations within the scopeof the claims and their equivalents are to be construed as beingincluded in the disclosure.

What is claimed is:
 1. A control method of an electronic device, themethod comprising: identifying at least one power transmitting devicefor transmitting wireless power to a power receiving device in acharging area; establishing a communication connection with the at leastone power transmitting device; generating a signal for controlling powertransmission of the at least one power transmitting device; andtransmitting, through the established communication connection, thesignal to the at least one power transmitting device to control thepower transmission of the at least one transmitting device to the powerreceiving device.
 2. The method of claim 1, wherein the controllingpower transmission of the at least one power transmitting devicecomprising adjusting a magnitude of power transmitted by the at leastone power transmitting device to a wireless power receiving device; 3.The method of claim 2, further comprising: identifying the magnitude ofthe power transmitted by the at least one power transmitting device, tothe power receiving device; and based on the identified magnitude of thepower, generating the signal indicating adjusting the magnitude of thepower.
 4. The method of claim 1, further comprising: determining whetheran interference is occurred by the power transmitted by the at least onepower transmitting device.
 5. The method of claim 4, wherein thedetermining comprises: detecting a number of the at least one powertransmitting device; and determining whether the interference isoccurred based on the detected number.
 6. The method of claim 4, whereinthe determining comprises: detecting a received signal strengthindicator (RSSI) of the at least one power transmitting device; anddetermining whether the interference is occurred based on the detectedRSSI.
 7. The method of claim 4, wherein the determining comprises:detecting a frequency channel being used by the at least one powertransmitting device; and determining whether the interference isoccurred based on the detected frequency channel.
 8. The method of claim1, wherein the signal indicates changing a period of a beacon of the atleast one power transmitting device.
 9. An electronic device,comprising: a communication interface; and a processor configured to:identify at least one power transmitting device for transmittingwireless power to a power receiving device in a charging area; establisha communication connection with the at least one power transmittingdevice using the communication interface; generate a signal forcontrolling power transmission of the at least one power transmittingdevice; and transmit, through the established communication connectionusing the communication interface, the signal to the at least one powertransmitting device to control the power transmission of the at leastone transmitting device to the power receiving device.
 10. The device ofclaim 9, wherein the controlling power transmission of the at least onepower transmitting device comprising adjusting a magnitude of powertransmitted by the at least one power transmitting device to a wirelesspower receiving device;
 11. The device of claim 10, wherein theprocessor is further configured to: identify the magnitude of the powertransmitted by the at least one power transmitting device, to the powerreceiving device; and based on the identified magnitude of the power,generate the signal indicating adjusting the magnitude of the power. 12.The device of claim 1, wherein the processor is further configured todetermine whether an interference is occurred by the power transmittedby the at least one power transmitting device.
 13. The device of claim12, wherein the processor is further configured to: detect a number ofthe at least one power transmitting device; and determine whether theinterference is occurred based on the detected number.
 14. The device ofclaim 12, wherein the determining comprises: detect a received signalstrength indicator (RSSI) of the at least one power transmitting device;and determine whether the interference is occurred based on the detectedRSSI.
 15. The device of claim 12, wherein the determining comprises:detect a frequency channel being used by the at least one powertransmitting device; and determine whether the interference is occurredbased on the detected frequency channel.
 16. The device of claim 9,wherein the signal indicates changing a period of a beacon of the atleast one power transmitting device.